Railway traffic controlling apparatus



Nov. 1, 1932. H. A. THOMPSON ET AL 1,385,875

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed June 24, 1931 2 Sheets-Sheet l l1 FLT/7 ornpson F'. /f. Main/can,

dam

M A TTORNEY.

Nov. '1, 1932.

H. A. THOMPSON ET AL RAILWAY TRAFFIC CONTROLLING APPARAT 2 Sheets-Sheet 2 INVENTORS. H. H.7'hom son, F-H.Mbh8/s8n, 815mm m ATTORNEY.

Filed June 24, 1931 mcswwm x \NQSR m 955% g Y Patented Nov. 1, 1932 riowann A. riaoivrrsonnnn FRANK H, mononsoiv, or iinenwooio, Reservists Union swrrcn & sienna conranv, on swissvernrrivns rt-g r 1 nssreivons to THE setse rig: k

, VANIA, aceia-r'onarrow on isnivnsrnvnnin L A tritnrr c comm tm APPARATUS Application filed June 24-,

Our invention relates. to railway i traiiic controlling apparatus and' particularly to apparatus of; the type involving trippinggdevices located in the trackway and cooperating withcarecarried apparatus to apply the brakes under unsafe traflic conditions 111 ad Vance." Y.

One feature of our invention is the pro vision of novel and improved means for per- 3 mitting the driver oatthe car to clear atripping device under unsafetrafiic conditions in advance and for simultaneously imposing a. safe low speed limit on the car.

. \Ve will describe two forms ofapparatus 'embodying our invention, and will then point ;-out the novel features thereof in claims. 1 v

In the accompanying drawings, Fig. 1 is a diagrammatic. view showing onc form of ap-;

zefparatus enihodyingour invention. Fig. 2 is a'sim lar view showing a modified form of the apparatus illustratedin Fig. 1, and also embodylngour invention Fig. 3 we plan view of; a car showing one. arrangement of 5*trip arms and contact shoes which may be employed in connection with the apparatus shown 1n Figs. 1 and 2.- r

Similar reference characters refer to simi: lar parts 1n each of the views.

30 Referring first to Fig. 1, the reference characters 2 and-2*"? designate the rails of a railway track along'which traffic normally moves in the direction indicated by the arrow. The rail QEisdivided, by means of insulated joints 3; to form a plurality of successivetrack here illustrated, is a transformer V, the secondary 31 of which is connected across the rails inseries with the usual current llmitlug iinpedance32. The primary 33 of trans former V is constantly supplied wtih. alter inatingcurrent from the terminals BX and- CK of a suitable source not shown inthe= drawing. Section T is also provided with a home relay H which may becontrolled in any suitable manner, the controllingcircuit for this relay being omitted. in orderto simplify 1921; Serial No. 546,514.;

biased to a projected position wherein it is illustrated iln dash l1nes,'b ut maybe moved'to a retracted POSltZOH when an o'pferatlng-v mechanism E is energized. Mechanism energized whenever the home relay H is energized the c rciut being from termlnaljBX of a source of alternating current,-th'rough 1' front contact 6 of relay H, and the operating mechanism E to terminal CX of the same source. Mechanism E is provided with the"; usualretaining circuit including a back'con tact 9 of track relay A anda contact 8. which Y isjclosed when .ind'onjly'when the element D is in its retracted position; the purposeofj this retaining circuit is to preventthe element- D from being released while a train ispa'ssing over it. Associated withthe mechanism E is a clearing relay 'Fwhich is normallyde energized, but which may beenergizedj mo-' mentarily from a source of current carried by the car as hereinafter explained. When re lay F is energizechan auxiliary circuit for the operating mechanism E will be closed; which circuit includes a'front contact 7 of relay. F and willbe obvious from thedrawmg. r Located on the car is a trip arm R which controls a brake application valve 26. t The trip arm R is arranged to be operated bythe trackway element Dv to open the valve 26 when the element vD is in its projected position but not when it is in its retracted position. Also located on the car in advanc'ejoffi the trip arm R isa contact shoe K whichnormally occupies a retracted position wherein it is shown inthe drawing. This shoe may bemoved. to a first projected position wherein it will engage the trackway element D when the latter is in its projected position but not when the. element is in. its retractedposition. The shoe 'K may also be moved to a second projected position wherein it will engage the ,drawing, fluid pressure is not supplied to. the fluid pressuredevice L, and the contact shoe K then occupies its retracted position under the influence of?! spring l l. When the valve device M is moved in counter-clockwise direction from the position inwhich it isshown int-he drawing, flu d pressure wlll be supplied from asuitable source through a PIP-'3,

2,5 and rotarymember 24 of the valve device M to the. upper end ofthe cylinder=28 of the inotonL. This fluid pressure will move a piston-13 downwardly, and this piston in turn will move the stem 11 and the shoe K to their first projected positions. This position is determined by the engagement of piston 13 with a shoulder 27in the cylinder 28 of the motor L. When thevalve M is moved in clockwise direction from the position in which it is shown in the drawing, fluid pressure will be supplied to the cylinder of motor L between pistons 13 and 12, and this fluid pressure will cause piston 12 to move downwardly thereby moving stem 11 and shoe K to their second projected positions. This position of the shoe is determined by the engagement of piston 12 with the lower end of the cylinder 28, and it will be observed that the stroke of piston 12 is longer than the stroke of piston 13.

' Vhen the shoe K is in its retraotedposition, two contacts 18 and 20 are closed.

When the shoe moves to its first projected position these contacts will be opened, and two other contacts 19 and 21 will be closed. WVhenthe shoe is moved to its secondprojected position all four contacts 18, 19, 20 and 21 will be open, and a fifth contact 22 will be closed. e

The reference character 'N' designates a train carried speed controlling relay; This relay is provided with a stick circuit which passes from a battery S, through contact 18,

the lower winding of relay N, front contact 17 of relay N and contact 20 to battery S.

It will beseen that this circuit is closed when and only when relay N is energized and the shoe K 1s 1n 1ts retracted position. When relay N is energized, a brake application valveQ, is energized by virtue of a circuit of relay N, and" the winding of valve Qto terminal C. Contact is arranged'to open when the speed of the car is above a safe low value, such, for exampe, as 15 miles per hour, and, consequently, it will be seen that when relay N is deenergized, a safe low speed limit is imposed on the car. i I

The operation of the apparatus is as follows: Assuming that home relay H is energized, so that the trackway element D :is in "its retractedpositiomthis element will be,

outof the pathof the'trip arm R, and, consequently, the element will have no influence 'to energize the clearing relay F. This cirjcuit is from battery S, through contact 21,

shoe K, trackway element D, back contact 5 of relay H, winding of relay F, ground at G, ground at G on the car, and contact 19 to battery S.' The closing of relay F will energize the operating mechanism E to retract the element D before this element coacts with the car-carried trip arm R, and the .on a car entering track section T. If, howelement D will then remain in its retracted" position, due to the retaining circuit for E through back contact 9 of relay A, until the car leaves section T. The'movement of the shoe K to its first projected position will,

however, openthe stickcircuit for relay N,

and this relay willremain deenergized even if the shoe K is restored to its retracted position. It follows that a low speed limit Will beimposed on the car while the car is traversing track section T. 7

When the car enters a section the element D for which is in the retracted position, the operator may move thecontact shoe K to its second projected position, thereby closing a pick-up circuit for car-carried relay N. This circuit is from terminal BX in the track-V way, through front point of contact 5 of relay H, trackway element D, contact shoe K, contact 22, primaryof a transformer lfi, and

ground G to terminal UK in the trackway. The secondary of transformer15 is connected with the upper or pick-up winding of relay N through a rectifier 16, so that this relay will then become energized. The contact shoe K may then be restored to its re tracted position, thereby closing the stick circuit for relay N. Relay N should be sufficiently slow-releasing in character in order to keep it closed during the transition from its pick-up circuit to its stickcircuit. The

closing of stick relay N will remove the speed limit, so that the car may then proceed without. restrictionuntil itencounters another.

trackway element D in proj ected' position.

:Referring Inow'to Fig. 2, as here shown, the contact shoe 'K is controlled by a fluid pressure device L which,-in turn, is controlled by a valve device M When them- 5 tarymember-ofthe valve device M occupies the position in which it is illustratedin the drawing, the u'pperend of thecylinder 2,8 of-the fluid pressure device L is connected with atmosphere through a pipe 41 rotary member of valve device M and. pipe 42. Under this condition, the piston 12 is moved, by means of the spring 1 4;to an upper position in which it is illustrated in the drawing. The partsare so proportioned that when the piston l2 occupies this position, the

shoe K willioccupy a retracted position in which it will; engage the trackway element D in'its projected position, but not when this element is in its retracted position. When the valve device M is moved in a counter-clockwise direction from the position in which it is illustrated in the drawing, fluid pressure will be supplied to theupper end of cylinder 28 from a suitable source not shown in the drawing, through a pipe 43, rotarymember 40'o'f valve device M and pipe 41. This fluid pressure will cause pis ton 12 to move downwardly until the piston engages the lower-end of the cylinder, there- 3 by moving stem 11 downwardly, and hence moving-shoe K to, a projected position in which it will engage the trackway element D in its retracted position.

The reference character W designates a 3 fluid pressure controlled brake application valve which is connected with the brake pipe by means of a pipe 52. As here shown, this valve comprises a valve member 47 which is biased by a spring 48 .to a lower position in which it closes an exhaust port 49 leading to atmosphere. The pressure on thetwo sides ofthe valve member 47 is equalized by a small equalizing port 50 in the side wall of the valve whereby, when the pipe 51 Connected 5 with the upper end of the valve -W isclosed,

the pressure is equalized and the valve-memher occupies its lower position wherein the exhaust port 49 is closed. If the pipe 51 is opened to atmosphere, however, the pressure on the upper side of the valve member 47 will be reduced, whereupon the brake pipe pressure on the lower side of this member will cause the member to be moved upwardly to 7 open the brake pipe to atmosphere through exhaust port 49, thus applying the brakes.

Member 47 will then remain in its upper po sition until the pressure in the brake pipe is reduced to a very small value whereupon this member will be restored to its lower or 3 closing position by the actionv of the spring Pipe 51 is connected with a pipe 53 through a magnet valve Q} which is closed when its in turn, is connected with atmosphere through a pilot valve Z and a port 54. The pilot valve Z is operated by the speed responsive device P, and is arranged to open when the speed of the car is above a safe low value, such for example as fifteen miles per hour. It will be apparent, therefore, that when valve Q is'energized, the pipe 51 is blanked, and the car may then travelwat any desired speech-but that, when the valve Q is deenergized, if the speed ofthe car exceeds the speed at which the pilot valve Z opens, pipe 51 will become connected with atmosphere through valve Q pipe 53, valve Z}, and port 54, and

valve W will then open and will apply the brakes. It follows, therefore, that a safe low speed limit is imposed on the car when valve Q is deenergized but not when this valve is energized.

Valve Q isprovided with a circuit which is controlled by thespeed controlling relay N, and which is closed onlywhen relay N is energized, this circuit passing from battery S through front point of contact 40 of relay N, and winding 55 ofvalve Q} back to battery S. Relay N is normally energized by virtue of a stick circuit which passes from battery S through front point of contact 40 of relay N, contact 44 of a manually controlled acknowledging switch U, and the lower winding of relay N back to batteryS. Contact-44 of acknowledging switch is normally closed, but is arranged to become open when switch U. is operated. Itwill be seen, therefore, that relay N will become deenergized when switch U is operated,

Switch U is-provided, in addition to the contact 44, with a normally closed contact 45 whichbecomes opened when the switch is operated, and with a normally open contact 46 which becomes closed when the switch is op era-ted. The function of the contacts 45 and 46 will become apparent as the description proceeds.

. Considering now the trackway portion of the apparatus shown 1n Flg. 2, the clearing relay,which is here designated]? is providedw-itha pickeup winding 38 and holding winding 39. The pick-upv winding 38 isar ranged to be attimes momentarily energized from the train-carried battery S over a picked in a stick circuit for relay F which stick circuit, passes from terminal X. of a suitable source of current not shown in the drawing through back contact 34 of track relay A, front contact 35of relay F and the holding winding '39 to terminal Y of the source. When relay F isenergized, it completes an auxiliary circuit for the mechanism E'which is similar to the clrc'uit previously described in connection with 1, with the exception that this circuit is controlled by front contact 56 of relay F instead of by contact 7 of relay F as shown in Fig. 1, The remainder of the trackway apparatus shown in Fig. 2 is similar to that shown in Fig. 1 with the exception that mechanism E ispro-vided with an auxiliary clearing circuit which causes mechanismfE to automatically become ener-, gized and move the trackway element D to its retracted position if a train which is moving in the opposite directionfrorn the normal direction of traffic enters section T from the right for any reason when the sectron T in rear of sectionT is unoccupied.

This auxiliary clearing circuit passes from terminal BX through front contact 36 of the track relay A for section T back contact 37 of track relay A, and mechanism E to terminal GK. 7

In explaining the operation of the apparatus shown in Fig. 2 as a whole, I will first assume that whenthe car enters section T,

home relay H is energized. Under these conditions, the trackway element D will be held inits retracted position by virtue of the circult for the mechanism E through contact 6 of relay fl, and the element D will therefore have no influence on the car, so that the car may proceed through the section at any desired speed. 7

I will next assume that when the car enters section T, relay H is .deenergized, so'that the trackway element D is inits projected position. Under'these conditions, unless the operator of the car takessuitable action, the element D will coact with the trip arm R to cause an automatic application of the brakes. If, however,'the operator is alertand operates the acknowledging switch U before the shoe K passes the trackway element D, and subsequently holds it in its operated position while the shoe is passing the trackway element, an automatic application of the brakes will be prevented in a manner which I will now explain. When switch U is operated, the stick circuit for relay N will become interrupted at contact 44 of switch U, and relay.

N will therefore become deenergized and will deenergize valve Q}. 7 As previously described, when valve Q, becomes deenergized, pipe 51 is connected with pipe 53, and a low speed limit will therefore then be imposed on the car. With relay N deenergized, so that the back point of its contact 40 is closed, and with contact 46 of acknowledging switch U closed, the engagement of the shoe K with the trackway. element D will complete the pickup 'circuitfor relay F previously referred to, this circuit passing from battery S through back point of contact 40 of relay N, contact 46 of acknowledging switch U, shoe K, trackway element D,-back' point of contact 5 of relay H, pick-up winding .38 of relay F ground at Gr, and ground at G on the car i back to battery S. Due to this pick-up cirturn will complete the retaining circuit for mechanism E. The function of the stick circuit for relay F is to insure that when relay F becomes energized due to the momentaryv closing of its pick-up circuit, it will subsequently remain energized for an interval of time which is long enough to cause mechanism E to move element D to its full retract ed position in which contact -8 is :closed. When the switch U is now restored to its normal position, relay N willremain deener- L.

gized, and it follows, therefore, that the low speed limit'will continue to be imposed on the car as long as the car remains in section T. When the car leaves section T, the sub sequent energization of track relay'A- will deenergize relay F which, in turn, will deenergize the mechanism E. The trackway portion of the apparatus will then be restored to the condition which it occupied when car entered the section.

tus to its normal position, the operator may the i In order to restore the car-carried appara-;

operate the valve M -to move the shoe 1C to its projected position while the car is passing a trackway element D 1n its retracted position. lVhen this is done, a pick-up circuit for relay N will be completed which passes from the right-hand terminal ofsecondary 31 of transformer V through front point of contact 50f home relayH, trackway element D, contact shoe K, contact 45 of acknowledgingswitchU, rectifierlG, the winding of relay N, rectifier 16 to ground at G and rail 2 to the left-hand side of secondary 31 of transformer V Due to this pick-up circuit, relay N wlll become energized and will close its stick circuit. The shoe Kmay then berestored to its retracted position, and

relay N will remain energized. The'energtz zation of relay'N- will-energize valve Q}, II.

which will remove'the speedlimit, and the car may then proceed without restriction un til it encounters another trackway element D= in its projected positiomj.

As illustrated in Fig. 3, each side of the car may be provided with a contact shoe IQ and a trip arm R, these elements being so arranged that regardless of the direction in which the car is moving, the contact shoe K will-alwaysencounter the vtrackway element 1 D before the trip arm R'encounters this element. I

Although we have herein shown and described only; two forms of apparatus embody-.

U cuit, relay F will become momentarily en ing our invention, it is understoodthat varis 1230 Havin thus described ourinvention what C 7 we claim i s '1. Railway trafiic controlling. apparatus comprising an element constituting a combined trippingdevice and contact arm locatedin the tracltway and movable to a. retracted era projected position according as traific conditions in advance are safe or unsafe, acar-carried brake applyingtrip arm arranged to be operated by said trackway element when the latter is in its projected position but not when it is in its retracted position, a manually controlled car-carried con: tact shoe adapted to at times engage said tracltway element in its projected position audio at other times engage said trackway element in its retracted position, means for at times moving said trackway element to its retracted position in response to engagement of said contact shoe and said traclrway element in its projected position and for imposing a low speed limit on the'car, and means for removing such speed limit restriction in response to engagement of said contact shoe and. the'traclrway element in its retracted position.

2, Railway tralfic controlling apparatus comprising an element constituting a combined tripping device and contact arm located in the traclrway and movable to a retracted or a'pro-jected position according as traffic conditions in advance are safe or unsafe, a car-carried brake applying trip arm arranged to be operated by said trackway element when the latteris in its projectedposition but not when it is in its retracted position, a carcarried contact shoe normally occupying a retracted position, manually controlled means for moving said shoe to a first projected position wherein it will engage said trackway' element when the latter is in its projected 'position'but not in its retracted position and for moving said shoe to a second projected position wherein it will engage the 'trackway element in th retracted position of the latter, means operating to move said trackway element to its retracted pos1-- tion in response to engagement the contact shoe inlts first pro ect-ed position and the trackway elementin ltS PIOJQCtGClPOSltion, means responsive to move ientot said Contact shoe to its first projected position for imposing a low speed limit on the car, and means for removing such speed limit restriction in response to engagement of said contact shoe in its second projected position and the trackway element in its retracted position.

3. Railway traific controlling apparatus comprising an element constituting a combined. tripping device and contact arm located in the. trackway and biased to a projected position, a home relay energized only under, safe traflic conditions in advance, a normally deenergized clearing relay, means for. moving said element .to a retracted position when. eitherfsaid home relay or said clearing'relay is energized, a car-carriedbrake applying arm arranged to be operated by said track way element when the latter is in its projectedposition but not when it is in its retracted position, a car-carried contact shoe normally occupying 1 a retracted position, manually controlled means for moving saidshoe to a first projectedpositionwherein it Will engage said trackway element in pro-' jected position but not in retractedlposition and for. moving said shoe to a second projected position wherein it will'engagesaid trackway element in retracted position, a carcarried speed'relay, a stick circuit'forsaid speed relay closed only when the relay itself is closedand saidshoe is in retracted position, a circuit for said clearing relayi including a carcarried source of current and closed only when the shoe inits first projected position engages the trackway: element in its projected position, .a pick-up circuitfor said speedrelay includinga track'- way source of currentand'closed only whensaid shoe in its second projectedposition engages said trackway element in its retracted position provided. said home relay is 'ener-- gized, and means :torimp'osin a' safe low speed limit on the car when sai speedrelaygis deenergized but not when it isenergized. 4. Railway traffic controlling. apparatus comprising an element constitutingacombined tripping'device and contact arm'located in the-trackway and movable to a retracted ora projectedposition according as traflic conditions in advance are safe or unsafe, a car-carried brake applying trip arm arranged to be operated by said Itrackway element when the latter is in its projected position but not when it is in itsretracted position, a car-carrying contact shoe normally occupying a retracted position in which it will engage said trackway element when the latter is in its projected position .but not in its retracted position, manually controlled means for movingsaid shoe to a: projected position wherein it will engage the-tr-ackway element in the retracted position of the; latter, manually controlled means for moving said trackway element to its retracted position in response to engagement ofthe contact binedtripping device and contact arm located in the trac-kway. and'movable to a retracted or aiprojected position according as trafiic condltionsin advance are safe orv unsafe, a car-earned brake applying trip arm arranged to be operated by said'track-- ment to its retracted position in response to engagement-of the contact shoe and the trackway element in its projected position and for imposing a low speed limit on the car, and'means for removing such speed limit restriction in response to-engagement of said contact'shoe'and the trackway element in its retracted position. 1

-6. Railway traffic controlling apparatus comprising an element constituting a combined tripping device and-contact armlocated in the trackway and movable to a retracted ora'projected position according as traffic conditions in advance are safe or unsafe, a car-carriedbrake applying trip arm arranged to be operated by said trackway element when the latter is in its-projected position but not when it is in its retracted position, a manually controlled car-carried contact shoe adapted to at times engage said trackway element in its projected position andto at other times engage said trackway element in its retracted position, an acknowledging switch on the car, a normally energized magnet valve on the car, means con trolled by said acknowledging switch and eiiective, when said switch is operated, for deenergizing said valve, means controlled by'said valve for imposing a low speed restriction on the car, means controlled by said acknowledging switch and effective when and only whensaid shoe engages said trackway element in its projected position for moving said trackway element to its retracted position, and means effective when said shoe engages said trackway element in its retralcted position for reene'rgizing said magnet va ve.

'7 Railway traific controlling apparatus comprising an element constituting a combined tripping device and contact arm lo cated in the trackway and movable to a retracted 'ora projected position according as traific conditions in advanceare safe or unvsate, a car-carried brake applying trip arm arranged to be operated by said t-ra'clrway element when the latter is in its projected position but not when it is in its retracted position, a manually controlled car-carried contact shoe adapted to at'times engage said tr'ackway element in its projected position and to at other times engage said trackway element in its retracted position, an acknowledging switch on the car, a normally ener-Iv gized' magnet valve on the car, means controlled by said acknowledging switch'and effective, when said switch is operated, for 'deenergizing'said valve, means effective when said valve becomes deenergized for impos-. ing a low speed restriction on the car, meanscontrolled by said acknowledging switch and:

elie ctive when and only when said shoe engages sa d trackwayelement in its pro ected position for moving said trackway element to its retracted position, and means effective when said shoe engages said trackway element in its retracted position for reenergizing said magnet valve. 4

8. Railway traific controlling apparatus comprising an element constituting a combined tripping device and contact arm 10*- cated in the trackway and movable to a retracted or a' projected position according as traffic conditions in advance are safe or unsafe, a car-carried brake applying trip arm arranged to be operated by said trackway elementwhen the latter is in its pro-' jected position but-not when it is in its re-- tracted position, a manually controlled carcarried contact shoe adapted to at times engage said trackway element in its projected position and to at other times engage said trackwayelement in its retracted position, anacknowledging switch on the car, a

pilot valve on the car controlled in accord' ance with the speed ofthe car, a magnet valve on the car, a brake application valve on the car controlled by said magnet valve and bysaidpilot valve, a speed controlling relay on the car,'means controlled by said relay for controlling said magnet valve, an acknowledging switch on the car, ,a stick circuits for said speed controlling relay controlled by a front contact of said speed con trolling relay and by said acknowledging switch,-means controlled by said acknowledging switch for moving said trackway element to its retracted position'in response to engagement of the contact shoe and the trackway element in its projected position, and

a pick-up circuit for said speed controlling tracted position, a manually controlled carof said speed controlling way element.

carried contact shoe adapted to at times engage said trackway element in its projected position and to at other times engage said trackway element in its retracted position, an acknowledging switch on the car, pilot valve on thecar controlled in accordance with the speed of the car a magnet valve on the car, a brake application valve on the car controlled by said magnet valve and by said pilot valve, a speed controlling relay on the car, means controlled by said relay for controlling said magnet valve, an acknowledging-switch on the car, a stick circuit for said speed controlling relay controlled by a frontcont'act of said speed controlling relay and by said acknowledging switch, means controlled by said acknowledging switch and bysaid speed controlling relay -for moving said trackway element to its retracted position in response to engagement of the contact shoe and tie trackway element in its projected position, and a pick-up circuit for said speed controlling relay controlled by said acknowledging switch and arranged to be closed when and only when said contact shoe engages said trackway element in its retracted position.

10. Railway traiiic controlling apparatus comprising an element constituting a combined tripping device and contact arm located in the trackway and movable to a re tracted or a projected position according as trafiic conditions in advance are safe or unsafe, a carjcarried brake applying trip arm I arranged to be operated by said traclrway element when the latter is in its projected position but not when it is in its retracted position, a manually controlled car-carried contact shoe adapted to at times engage said I trackway element in its projected position and to at other times engage said trackway element in its retracted position, an acknowledging switch on the car, a pilot valve on the car controlled in accordance with the T speed of the car, a magnet valve on the car,

a brake application valve on the car, means efi ective when saidmagnet valve is deenergized for controlling said brake application valve by said pilot valve, a speed controlling relay on the car, means for energizing said magn t valve when and only when said relay is energized, an acknowledging switch on the a stick circuit for said speed controlling relay controlled by a front contact relay and by said aclniowledging switch, means controlled by said aclmowledging switch for moving sait trackway element to its retracted position in response to engagement of the contact and the trackway element in its projected position, and a pick-up circuit for said speed controlling relay arranged to be closed when said contact shoeengages said traclrway element in the retracted position of the track 11. Railway'trafiic controlling apparatus comprising a stretch of railway track provided with a track circuit including a tr ck relay, an element 1 constituting a l combined tripping device and contact armlocated 1n the t-rackway and biased to a projected position, a home relay energized only under safe rai'iic conditions in advance,- a normally doenergized clearing relay, means for moving said element lto a retracted position when either said homo relay or said clearing'relay is energized, 'a car carried brake applying trip arm arranged to be operated by sait trackway element when the latter is in its projected position but not when it is in its retracted position, a manually controlled carcarried Contact shoe adapted to at times engage said traclrway element in its projected position and to at other times engage said lrway element in its retracted position, means on the car for energizing said clearing relay in response to engagement of said shoe and said tracliway element in its projected position and for imposing a low speed limit on the car, and means for removing such speed limit restriction in response to engage ment of said contact shoe and the trackway element in its retracted position.

12. Railway tratiic controlling apparatus comprising a stretch of railwaytrack provided with a track circuit including a track relay, an element constituting arcombined tripping device and contactarm located 'in the trackway and biased to a pr jected positi :1, a home relay energized only under safe traffic conditions in advance, a normally doenergized clearing relay, a' stick circuit for salt. clearing relay including aback contact of said track relay anda front contact/oi said eari-ng relay, means for moving said element to a retracted position when either said home relay or said clearing relay is energized, a ar-carried brake applying trip arm arranged to be ope ated by said trackway element when the latter is in its'projected position but not when it is in its retracted posicomprising two adjacent sections of railway track overwhich trarlic normally moves in both directions, a trackway element constituting combined tripping device and contact arm associated with the forward section ailway traiiic controlling apparatus and biased to a pro ected position, means automatically moving said arm to a retracted position if a car moving in the opposite direction from the normal direction of traffic enters the forward section-when the rearsection is unoccupied, a car-carried brake applying trip arm arranged. to be operated by said trackway element when the latter is in its projected position out not when it is in its retracted position, a manually controlled car-carried contact shoe adapted to at times engage said trackway element in its projected position and to at othertimes engage said trackway element in its retracted position, means for vmoving said traclcway element to its retracted position in-response to engagement of said shoe and said traclrway element in its projected position and for. imposing a low speed limit on the car, and means for removing such speed limit restric tion in response to engagement of said contact shoe and the trackwayelement in the retracted position of the latter.

14. Railway trafic controlling apparatus comprising two adjacent sections of railway track. over which trafiic normally moves in one direction, a track circuit for each section including a track relay, a trackway element constituting a combined tripping device and contact arm associated with the forward section and biased to a projected position, mechanism for moving said trackway element to a retractedposition, a home relay associated with the forward section and energized only under safe traffic conditions in advance, a normally deenergized clearing relay associated with the forward section, a first circuit for said mechanism including a front contact of said clearing relay, a second circuit for said mechanism including a front contact of the track relay for the rear section and a back contact of the track relay for the forward section, a contact controlled by said trackway element and arranged to be closed when and only when said trackway element occupies its retracted position, a third circuit for said mechanism including said trackway element controlled contact and a back contact of the track relay for the forward section, a fourth circuit for said mechanism including a-front contact of said home relay, a stick circuit for said clearing relay including-a front contact of said clearing relay and a back contact of the track relay for the forward section, acar-carried brake ap plying trip arm arranged to be operated by said trackway element when the latter is in its projected position but not when it is in its retracted position, a manually controlled car-carried contact shoe adapted to at times engage said trackway element in its projected position and to at other times engage said trackway element in its retracted position, means for at times momentarily energizing said clearing relay in response to engagement of-said shoe and said trackway element in its projected position and for simultaneously imposing a low speed limit on the car, and means for removing such speed limit restrict-ion in response to engagement of said contact shoe and the trackway element in its retracted position. v

a 15.- Railway traffic controlling apparatus comprising two adjacent sections of railway track over which trailic normally moves in one direction, a track circuit for, each sec-- tion including a track relay and a source of current, a trackway element constituting acombined tripping device and contact arm associated with the forward section and biased to a projected position, mechanism for moving said trackway element to a retracted position, a home relay associated with the forward 7 section and energized only under safe trafic conditions in advance, a normally deenergized clearing relay associated with the forward section and provided with a pick-up and a holding winding, a first circuit for said mechanism including a front contact of said clearing relay, a second ci-rcuit for said mechanism includinga front contact of the track relay for the rear sec. tion and a back contact of the track relay for the forward section, a contact controlled by said-trackway element and arranged to be closed when and only when said tra'ckway element occupies its retracted position, a third circuit for said mechanism including said trackway element controlled contact and a back contact of the track relay for the forward section, a fourth circuit for said mechanism including a front contactof said home relay, a stick circuit for said clearing relay including a front contact of said clearing relay and a back contact of the track relay for the forward section, a car-carried brake applying trip arm arranged to be operatedby said trackway element when the latter is in its projected position but not when it is in its retracted position, a manually controlled car-carried contact shoe adapted to at times engage said traclrway element in its projected position and to at other times engage said trackway element in its retracted position, an acknowledging switch on the car provided with two normally closed contacts which become opened when the switch is operated and a normally open, contact which becomes,

closed when the switch is operated, a speed controlling relay on the car; a stick circuit for said speed controlling relay including a car-carried source of current, a front contactof said speed controlling relay, and a first one of the normally closed contacts of is energized; a circuit for said magnet Valve including a car-carried source of current and a front contact of said speed controlling relay; a pick-up circuit for said clearing relay including a car-carried source of current, a back contact of said speed controlling relay, the normally open contact of said acknowledging switch, said shoe and said trackway element; and a pick-up circuit for said speed controlling relay including the source of current for the rear track section, a front contact of said home relay, said shoe, said trackway element, and the remaining normally closed contact of said acknowledging switch.

In testimony whereof we affix our signatures.

HOWARD A. THOMPSON. FRANK H. NICHOLSON. 

